1. Technical Field
The present invention relates to a bias power supply device and an image forming apparatus.
2. Related Art
In an image forming apparatus such as an electrophotographic copying machine, an electrostatic latent image is formed on a photoconductive drum, a toner image is formed by developing the electrostatic latent image, and thereafter, the toner image is transferred onto a recording sheet or the like. In such an image forming apparatus, the surface of the photoconductive drum is charged to a predetermined potential (charging bias) to form the electrostatic latent image on the photoconductive drum. Moreover, a predetermined potential (developing bias) is applied to a developing unit to form the toner image by developing the electrostatic latent image formed on the photoconductive drum. For generation of such a charging bias or a developing bias, bias power supply devices of a harmonic modulation method have been used. The bias power supply devices of the harmonic modulation method are very effective in energy savings.